Off-peak water heating system



Dec. 16, 1941. H. M. BIEBEL OFF-PEAK WATER HEATING SYSTEM Filed March 31, 1941 IN VENTOR. flERMA/VM 3/5354 ATTORNEY.

Patented Dec. 16, 1941 OFF-PEAK WATER HEATING SYSTEM HermanM. Biebel, Elfin, 111., assiznor to McGraw Electric Company, Elgin, 11]., a corporation of Delaware Application March 31, 1941, Serial No. 385,978

6 Claims.

wheel 29. While I have shown a worm gear and a worm wheel for illustrative purposes, I desire it to be understood that the object is to provide a clock or continuously operative timer effective to cause one revolutionof a certain part of the system once in twenty-four hours and any mechanical means for obtaining this purpose may be employed by me in place of the worm gear and worm wheel shown in the drawing.

The worm wheel 29 is fixedly mounted on a rotatable shaft 3| and while I have not shown any bearing for this shaft, it is, of course, understood that such means are provided to permit of rotat- Other objects of my invention will either be apparent from a description of several modifications embodying my invention or will be pointed out hereinatfer in the course of such description and set forth in the appended claims.

In the drawing: I

Figure 1 is a view of a domestic hot water tank with a diagrammatical layout of a control system embodying my invention, the parts being shown in positions they will occupy just before the start of an off-peak period and with the tank containing coldyvater,

Fig. 2 is a fragmentary view similar to Fig. 1 but showing parts of the control means in the positions they will occupy at the start of an offpeak period and with the tank partly full of hot water, and,

Fig. 3 shows a modification of my improved water heating system, the parts being shown in the positions they will occupy when the tank is substantially filled with cold water.

I have elected to show my improved hot water heating system as applied to a domestic tank ll, shown as being of cylindrical shape and relatively tall, although my invention is not limited thereto. I provide a cold water inlet pipe l3 and a hot water outlet pipe suitably connected to the tank H which may be surrounded by heat insulating material I! which may be protected by an outer casing l9, all in a. manner well known in the art.

I provide an electric heater 2| which, for coning the shaft 31 by the motor 25.

I provide a stationary cam disk 33 loosely mounted on the shaft 3i, which cam disk has a larger part of its outer periphery of a uniform radius, which radiu is less than the outer radius of a portion 35 which portion 35 constitutes, in eifect, a part of the off-peak period desired by the utility providing the electric current to operate the system and energize the heater 2|. The cam disk 33 is held stationary by any suitable I means, not shown.

venience, may be clamped around the outside of means which is shown as including an electric motor 25 having a worm gear 21 mounted on its I have shown a supporting bearing bracket 31 which may be suitably supported from or by the tank H at itslower end and I further show a tubular bushing 39 movably mounted on the shaft 3! at that end thereof near the tank H. The bushing 39'is provided with a radially extending arm 4! having insulatedly mounted thereon a member 43 of electric conducting material which member has a peripheral extent of such dimension that when added to the peripheral extent of portion 35 of disk 33, the time covered by the leading portion 43 and the trailing portion 35 will equal the desired off-peak period. Member 43 is insulated from arm 4!, for a purpose which will hereinafter appear. I

I provide an annular ring 45 mounted on and insulated from the shaft 31 which contact ring is adapted to be engaged by a brush 41. I further provide a supporting arm 49 fixedly mounted on shaft 3| which arm is adapted to support a brush or contact arm 5| shown as being supported by arm 48 by means of a block 53 of electric insulating material. Contact ring 45 is con nected to brush 5| by a conductor 55. It is understood that cam disk 33 is either of electric conducting material or that the portion 35 thereof, of larger outer radius, is of electric conducting material since it is desired to have the brush 5! engage the portion 43 as well as the portion 35 to close an electrical circuit, as will be hereinafter shaft which is adapted to mesh with a worm described.

H or, as may be stated in other words, in accordance with the heatrcondition or the heat content of the tank. For this purpose I provide a rod 51 which isshown as being of non-expansible material, now well known in the art, which has its upper end supported by a bracket 59 which may be secured in any suitable or desired manner to the upper end of the tank. The lower end of rod or bar 51 may have a plurality of teeth out therein which will enable it to mesh with an end portion of the bushing 39 whereby longitudinal movement of the lower end of the rod 51 will cause turning movement of bushing 39 and therefore an angular or peripheral movement of portion 43 of the contact comprising two relatively adjustable members 43 and 35 adapted to be engaged by brush 5|.

Apair of supply circuit conductors El and 63 are shown to which the terminals of the motor 25.

are permanently connected. Supply circuit conductor 6| is connected by a conductor 65 with brush 41. Supply circuit conductor 63 is connected by a conductor 61 with one terminal of the heater 2|, the other terminal of which is connected to one terminal of a thermal heater control switch 69 which is shown as including a bimetal bar 'I| having one end secured to a block I3 or other suitable support which is understood to be in heat-receiving relation with the tank II or with the water in the tank. Thermal switch 69 includes further a fixed contact member 15 adapted to engage with and be disengaged from the free end of bimetal bar 1|. Contact 15 is connected through a conductor 11 with the electric conducting member 43.

Let it be assumed that the tank II has just been filled with cold water and that the parts are in the position shown in Fig. 1 of the drawing,

- that is, just before the start of an off-peak peber 43, which may be called the auxiliary leading portion, a circuit through the heater 2| will be established substantially'as follows: From supply circuit conductor 6| through conductor 65 and brush 41 to the contact ring 45, through conductor 55 and brush 5| to the leading portion 43 and from there through a suitable conductor 19 through conductor 11 to contact member 15, through bimetal bar II which will be in engagement with contact member 15 under the assumed conditions and from there through heater 2| and conductor 61 to the other supply circuit conductor 63. This will therefore energize the heater 2| atsubstantially the beginning of an ofi-peak period. I have shown the peripheral extent of the main trailing portion and of the movable auxiliary leading portion 43 as extending over substantially one-third of the entire periphery,

- that is, the time extent will be substantially eight hours. For illustrative purposes it may be assumed that such maximum off-peak period or energization of the heater will start at 10 p. m. and extend to substantially 6 a. m.

While I have hereinbefore stated that the position of the leading portion 43 of the contact surface adapted to be engaged by brush 5| is that corresponding to the condition when the tank is entirely full of cold water, I do not desire to be limited thereto since it is possible to so construct and adjust the operative parts of my system, particularly that of the auxiliary leading portion 43 of the contact surface, so that the position shown in Fig. 1 of the drawing will corre spond to that condition of the tank when a predetermined fractional part of the water content is hot.

Fig. 2 of the drawing shows the condition when the tank is not entirely filled with cold water but when it contains a predetermined fractional part of hot water with the result that the leading portion 43 overlaps the trailing portion 35 and the brush 5|, which is moved continuously in a clockwise direction, will not engage portion '43 at as early a time as it would have engaged member 43 under the conditions shown in Fig. 1 of the drawing. The adjustment of the system is, of course, such that the entire content of the tank will be heated shortly before the end of an oil-peak period, that is, the energization of the heater 2| will be effected to occupy the "valley of the load curve on the central station.

It is further obvious that should all of the water in the tank be heated to the desired high temperature before the end of the oil-peak period, the bimetal bar would flex and disengage from the contact member 15. It is further evident that should a withdrawal. of hot water from the tank occur during the rest of the ofi-peak period, the bimetal bar would again engage contact member 15 and reenergization of the heater 2| would occur and might continue until deener-- which certain parts of the system hereinbefore described are used in combination with others whereby I am enabled to obtain other results than are obtained by the use of the system shown in Figs. 1 and 2.

I provide an electric motor 25 having a worm gear 21 on its shaft meshing with and driving a worm wheel 23 which worm wheel 29 is fixedly mounted on a shaft 8|. It is to be understood that while no particular supporting means have been shown for shaft 8|, these are to be provided in a manner well known in the art.

I provide a fixed arcuate contact surface 83 which may be fixedly mounted on a suitable supporting means 84 of electric-insulating material.

I provide further an adjustable leading contact surface 85 which is supported by a bushing 81 movably mounted on shaft 8| to which the portion 85 is connected as by an arm 89. The bushing portion 81 is provided with teeth to permit of meshing with the toothed lower end of a nonexpansion rod 51 of the same general kind as hereinbefore described in connection with Fig. 1 of the drawing. I provide further a second bushing 9| fixedly mounted on shaft 8| and having either secured thereto or integral therewith a brush or contact arm 93 which is adapted to encase the movable auxiliary leading portion 85 and the fixed main trailing portion-83 of the contact surface which has substantially the same operation as the members 43 and 35 hereinbefore described in connection with Figs. 1 and 2 of the drawing.

1 provide in addition to the thermal heater control switch 68 subject to the temperature of the water in the lower portion of the tank. a secend heater control switch comprising an electro- -magnetic coil 95 adapted to energize a movable core member 81. A main contact bridging member 88 and an auxiliary holding circuit contact bridging member IOI are mechanically connected with the movable core 81 to be moved into engagement with, respectively, fixed main heater circuit contact members I03'and auxiliary fixed holding circuit contact members I05. Supply circuit conductor ii is connected by a conductor I01 with one of the fixed contact members I08 and III, while the other fixed contact member III is connected by a conductor I08 with one terminal of the heater 2|. The other terminal of heater H is connected to contact member 13 and contact member I5 is connected by a conductor III with the other supply circuit conductor 88. Supply circuit conductor iI'is connected by a conductor II3 with brush 5! and the two electrically connected contact surfaces 85 and 83 are connected by a conductor 1 I5 with one terminal of coil 95. The other terminal of coil 95 is connected by a conductor III with contact member 13 of the thermal switch 59.

When brush 93 is engaged with the leadingcontact surface 85 moved peripherally relatively to the trailing portion 83 in accordance with the average water temperature of the heat content of the tank, an energizing circuit through coil 85 will be established as follows: From supply circuit conductor BI, through conductor 3, brush 5i to bushing 9i, through arm 93 and through the contact surfaces 85 and 83 and the mechanical support 84 supporting the latter, through conductor II5, coil 95, through conductor I", through the thermal switch 89 and from there through conductor III to the other supply circuit conductor 83. This energization of coil 95 will cause upward movement of core 91 and of the contact bridging members 99 and NI into engagement with the respective fixed contact members I03 and I05 whereby an energizing circuit through the heater 2i is established, as well as a holding circuit for the coil 95. The energizing circuit through heater 2i is substantially as follows: From supply circuit conductor 8I through conductor I01, through engaged contact members I03 and 99, through conductor I09, through heater 2| and then thermal heater control switch 69 and from there through conductor III to the other supply circuit conductor 63.

ductor I01 to one of the fixed contact members I05, from there through the engagedcontact' member I M and I05 and a conductor II9 to and through coil 95 and from there through conductor I ii and the closed thermal switch 89 through conductor III to the other supply circuit conductor 53.

The position of the thermally movable auxiliary leading contact surface 85 is the same. as was hereinbefore described in connection'with the system shown in Fig. 1 of the drawing. That is, if the tank contains either a large amount of cold water or is entirely full of cold water at the start of an off-peak period, the relative positions of th leading and the trailing portions of the contact surface is substantially that shown in Fig. 3 of the drawing but the leading portion 88 may occupy the position shown in the broken lines in Fig. 3 of the drawing if the tank contains an appreciable amount of hot water which can be heated in less than an entire offpeak period.

It is further evident that the holding circuit described above is entirelyindependent of the engagement of brush 83 with the contact surface 85 and 83 so that should it happen that all of the water in the tank is not hot at the end of an off-peak period because of the fact that appreciable amounts of hot water were withdrawn from the tank during the later part of an oi!- peak period, energization of the heater II will continue beyond the end of an off-peak period and in fact will continue until substantially all of the water in the tank is hot, at which time bimetal bar II will fiex to be disengaged from the fixed contact 15 whereby the holding circuit of the electromagnetic switch and particularly of the coil is interrupted with attendant deenergization of the coil 95, opening of the electromagnetic switch contacts and therefore deenergization of the heater 2i.

A normally open push button switch I2I may be provided, one fixed contact i23 thereof being connected to supply circuit conductor GI while the other fixed contact member I23 is connected by a conductor I25 to conductor H5. When the switch I2I is closed manually and momentarily by an operator, an energizing circuit through the coil 95 will be established as can easily be traced from Fig. 3 of the drawing with the result that contact bridging member 99 is moved into engagement with contact members I08 whereby the heater 2| is energized while at the same time the hereinbefore described holding circuit is established by engagement of contact bridging member IOI with the fix contacts I05. Should it happen accidentally or because of unusual demands for hot water during the day, that is, during the on-peak period of a day, that the user of such a system would desire or require hot water, all that it would be necessary to do would be to close switch I2I momentarly when the heater would be energized, such energization continuing until all of the water in the tank is hot when deenergization of the heater 2i would occur, all as described above.

The water heating systems embodying my invention and disclosed in the present application therefore are effective to' cause energization of the heater of a hot water tank at a time varying in accordance with the amount of hot water in the tank at the start of an ofi-peak period, energization being delayed if the tank contains more than a predetermined amount of hot water. The systems will either cause deenergization of the heater at the end of an oil-peak period when the modification shown inFig. 1 of the drawing is used or energization may continue beyond the end of an off-peak period when a second heater control switch of the electromagnetic type is used as shown in Fig. 3 of the drawing.

Various modifications may be made without departing from the spirit and scope of the invention and I desire that all such modifications clearly coming within the scope of the appended claims shall be considered to be covered thereby.

I claim as my invention:

1. In an oif-peak water heating system for a tank havingan electric heater, a switching means for controlling said heater including a movable contact member. a constantly operative timer adapted to move said contact member in a given path, a contact surface extending over an of!- peak portion of said given path and comprising a fixed main trailing portion and a movable auxiliary leading portion and means responsive to the average tank water temperature for fixing the position of said auxiliary leading portion of said cam surface to cause engagement of said cam surface by said movable contact member at a time during an off-peak period which is later when the average tank water temperature is high than when it is low.

2. In an ofi-peak water heating system for a tank having an electric heater, a switching means for controlling said heater including a movable contact member, a constantly operative timer adapted to move said contact member in a given path, a contact surface extending over an Ofl! peak portion of said given path and comprising a fixed main trailing portion and a movable auxiliary leading portion and means responsive to the average tank water temperature for fixing the position of saidauxiliary leading portion of said cam surface to cause engagement of said cam surface by said movable contact member at a time after the start of an ofipeak period which time increases in accordance with the excess of the average tank water temperature'above a pre-' determined value.

3. In an ofi-peak water heating system for a tank having an electric heater, an electromagnetic heater control switch and a thermallyactuable heater control switch electrically connected in series circuit with each other, a continuously operative timer, a movable contact member adapted to be moved in a given path by tinuously operative timer, a movable contact member adapted to be moved in a given path by said timer, a contact means having a surface engageable by said movable contact member and extending over an off-peak portion of said given path and comprising a fixed trailing main portion and a movable leading auxiliary portion and means responsive to the average tank water temperature for moving said leading auxiliary portion of said contact means relatively to said main portion to cause engagement of said movable contact member with said leading auxiliary portion and energization of the electromagnetic switch and of the electric heater after a length of time after the start of an oil-peak period which length of time increases in proportion to the excess or hot water in the tankovera predetermined amount and for causing deenergization of'said heater when substantially all of the water in the tank is hot.

5. In an ofl-peak water heating system for a tank having an electric heater, an electromagnetic heater control switch and a thermallyactuable heater control switch electrically connected in series circuit with each other, a continuously operative timer, a movable contact member adapted to be moved in a given path by said timer, a contactmeans having a surface engageable by said movable contact member and extending over an oii-peak portion of said given path and comprising a fixed trailing main portion and a movable leading auxiliary portion and means responsive to the average tank water tempcrature for moving said leading auxiliary portion of said contact means relatively to said main said timer, a contact means having a surface engageable by said movable contact member and extending over an oii-peak portion of said given path and comprisinga fixed trailing main portion and a movable leading auxiliary portion and means responsive to the average tank water temperature for moving said leading auxiliary portion of said contact means relatively to said main portion to cause engagement of said movable contact member with said leading auxiliary portion and energization of the electromagnetic switch and of the electric heater after a length of time after the start of an off-peak period which length of .time increases in proportion to the excessmf hot water in the tank over a predetermined amount.

4. In an ofi-peak water heating system for a tank having an electric heater, an electromagnetic heater control switch and a thermallyactuable heater control switch electrically connected in series circuit with each other, a conportion to cause engagement of said movable contact member with said leading auxiliary portion and energization of the electromagnetic switch and of the electric heater after a length of time after the start of an off-peak period which length of time increases in proportion to the excess of hot water in the tank over a predetermined amount for causing deenergization of said heater when substantially all of the water in the tank is hot and for causing reenergization of said heater in case withdrawal of hot water from the tank during the rest of an oif-peak period substantially reduces the amount of hot water in the tank. I

6. A system as set forth in claim 3 and including a normally open switch movable into momentarily closed position to cause energization of said electromagnetic switch and of said heater at any desired time during an on-peak period in case less than all of the water in the tank is hot, said energization of the heater continuing until substantially all of the water in the tank is hot. 1

HERMAN M. BIEBEL. 

